System and Method for Estimating Cardiac Pressure Based on Cardiac Electrical Conduction Delays Using an Implantable Medical Device

Abstract

Techniques are provided for estimating left atrial pressure (LAP) or other cardiac performance parameters based on measured conduction delays. In particular, LAP is estimated based interventricular conduction delays. Predetermined conversion factors stored within the device are used to convert the various the conduction delays into LAP values or other appropriate cardiac performance parameters. The conversion factors may be, for example, slope and baseline values derived during an initial calibration procedure performed by an external system, such as an external programmer. In some examples, the slope and baseline values may be periodically re-calibrated by the implantable device itself. Techniques are also described for adaptively adjusting pacing parameters based on estimated LAP or other cardiac performance parameters. Still further, techniques are described for estimating conduction delays based on impedance or admittance values and for tracking heart failure therefrom.

Description

RELATED APPLICATIONS [0001]This application is related to U.S. patent application Ser. No. ______ (Attorney Docket No. A07P3015-US1) of Wenzel et al., entitled, “System and Method for Estimating Cardiac Pressure Based on Cardiac Electrical Conduction Delays Using An Implantable Medical Device,” filed concurrently with this application. This application also claims priority on U.S. Provisional Patent Application No. 60 / 910,060 of Wenzel et al., entitled, “System and Method for Estimating Left Atrial Pressure based on Intra-Cardiac Conduction Time Delays,” filed Apr. 4, 2007, which is fully incorporated by reference herein.FIELD OF THE INVENTION [0002]The invention relates generally to implantable medical devices such as pacemakers and implantable cardioverter defibrillators (ICDs) and in particular to techniques for estimating cardiac pressure (particularly left atrial pressure (LAP)) to detect and evaluate heart failure and related conditions and to automatically adjust pacing param...

AI Technical Summary

Benefits of technology

This approach provides reliable estimation of LAP, enabling effective tracking and management of CHF, improving cardiac function and reducing susceptibility to life-threatening arrhythmias, while also allowing for adaptive adjustment of pacing therapies.

Problems solved by technology

The conduction time delay between the contraction of any two cardiac chambers following either a natural occurring stimulus or an externally administered stimulus is indicative, in at least some patients, of the degree of cardiac failure, such that longer delays may be associated with a worsening cardiac status.

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